DESCRIPTION (Applicant's Description): The Cancer Surveillance Program (CSP) is the rapid ascertainment population-based cancer registry for Los Angeles County. All three projects described in this Program Project Grant application, as well as a series of separately funded analytic epidemiologic studies, depend on the CSP for rapid case identification. Since 1987, the majority of funding for the day-to-day activities of the CSP has come from the State of California, through the California Cancer Registry (CCR). The CSP is one of ten regional registries of the CCR, which together provide complete coverage of the State. In 1992, the CSP became the newest and largest of the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) collaboration of registries. Funds requested by this application will support the rapid ascertainment (RCA) component of the CSP, which will be utilized by all three projects. The CSP also provides demo graphic details on changing patterns of cancer which have proven invaluable in providing clues to iatrogenic hypotheses. It maintains a tracing laboratory for tracing prevalent cancer patients which will also be utilized by Project C. The major focus of the CSP has always been and will continue to be etiologic research. The major distinctive features of the CSP include (1) the size and diversity of the population base; (2) both active and passive surveillance; and (3) rapidity of case ascertainment. The latter feature is a high priority of the CSP. RCA activities include the identification of all new cases through regular screening of pathology reports at all facilities where cancer is diagnosed. For patient reports qualifying for ongoing studies (currently totaling about 13,100 reports annually) a minimal data set is abstracted by CSP Field Technicians. Patients with potentially rapidly fatal diseases are reported by fax to the CSP office on the day of ascertainment to further enhance rapidity of ascertain ment. The average interval from date of pathology to the date that the pathology report is delivered to the study investigator is four weeks.